Various uses are known for controlled atmosphere furnaces. For example, as part of a manufacturing process, it may be desirable to condition a material or article of manufacture by heating it in the presence of hydrogen. Such systems are sometimes referred to as hydrogen furnaces. In such applications, there is a need for apparatus and methods for providing and processing the hydrogen, as well as for operating an integrated system.
A variety of hydrogen-based electrochemical fuel cell technologies are known, wherein electrical power is produced by reacting a fuel such as hydrogen in an electrochemical cell to produce a flow of electrons across the cell, thus providing an electrical current. For example, in fuel cells utilizing proton exchange membrane technology, an electrically non-conducting proton exchange membrane is typically sandwiched between two catalyzed electrodes. One of the electrodes, typically referred to as the anode, is contacted with hydrogen. The catalyst at the anode serves to divide the hydrogen molecules into their respective protons and electrons. Each hydrogen molecule produces two protons which pass through the membrane to the other electrode, typically referred to as the cathode. The protons at the cathode react with oxygen to form water, and the residual electrons at the anode travel through an electrically conductive path around the membrane to produce an electrical current from anode to cathode. The technology is closely analogous to conventional battery technology.
Electrochemical cells can also be used to selectively transfer (or “pump”) hydrogen from one side of the cell to another. For example, in a cell utilizing a proton exchange membrane, the membrane is sandwiched between a first electrode (anode) and a second electrode (cathode), a gas containing hydrogen is placed at the first electrode, and an electric potential is placed between the first and second electrodes, the potential at the first electrode with respect to ground (or “zero”) being greater than the potential at the second electrode with respect to ground. Each hydrogen molecule reacted at the first electrode produces two protons which pass through the membrane to the second electrode of the cell, where they are rejoined by two electrons to form a hydrogen molecule (sometimes referred to as “evolving hydrogen” at the electrode).
Electrochemical cells used in this manner are sometimes referred to as hydrogen pumps. In addition to providing controlled transfer of hydrogen across the cell, hydrogen pumps can also be used to separate hydrogen from gas mixtures containing other components. Where the hydrogen is pumped into a confined space, such cells can be used to compress the hydrogen, at very high pressures in some cases.
There is a continuing need for apparatus, methods and applications relating to hydrogen furnaces.